ISSN:
1573-2568
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Whole colon perfusion studies and measurements of luminal prostaglandin E2 were carried out in a 41-year-old female with collagenous colitis to investigate pathophysiological mechanisms for the diarrhea. Biopsies of the colorectal mucosa had revealed a continuous 25- to 60-μm subepithelial collagenous layer, but normal junctional complexes and capillaries. When the patient fasted, the diarrhea persisted and fecal electrolytes, as estimated from the concentration of sodium, potassium, and their anions, accounted for all the osmolality (284 mosm/kg) of stool water, the pH of which was above 8.0. The lumen-negative electrical potential difference in the rectum was −64 mV vs −45±2 mV (mean±sem) in healthy controls. Profuse secretion of fluid and electrolytes occurred during colonic perfusion with saline. Transport of sodium appeared to be passive with flux ratios equal to those predicted for passive sodium movements, while chloride transport against a steep electrical gradient indicated active secretion. Perfusion with an “ileal output”-like solution decreased fluid and electrolyte secretion, suggesting that bicarbonate, in addition to chloride, may be a major determinant of secretion rates. Since immunoreactive prostaglandin E2 levels followingin vivo equilibrium dialysis of feces ranged from 555 to 650 pg/ml vs 55 to 235 pg/ml (99% confidence limits) in healthy controls, it is speculated that prostaglandins synthesized locally in response to mucosal hypoxia might be the mediators of anion secretion.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01295815
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